Fluidized treating operation



Oct. 19, `1954 ||I Z MARTIN 4 2,692,192

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Home!" Z. mariti?. nvanbof Patented Oct. 19, 1954 UNITED STATES PATENTOFFICE 2,692,192 FLUIDIZ'ED TREATING OPERATION Homer Z'. Martin,Cranford, N. J., assignor to Standard i1 Development Company, acor-poration of Delaware Application June 27, 1951, Serial No. 233,731

6 Claims. l

This application is a continuation-in-part of application Serial No.689,769, filed August l0, 1946, for Improved Fluidiaed TreatingOperation, now abandoned,

The present invention is concerned with proc'- es'ses relating to thecontacting of subdivide-d fine solid particles and gases. he inventionper-- tains more particularly to processes wherein separate and distinctuidized phases of ne subdid vided solid particles are maintained in atreating zone, and wherein one nuidized phase is caused to flow througha second uidized phase. It also pertains more particularly to a processof, and an apparatus for contacting solids with upowing gases in whichthe gases pass through an enlarged contacting chamber containing a bodyof subdivided ne solids at a controlled rate tc main'-V tain thesubdivided solids in anp'lurality of fluid phases, which phases are in arelativelyI turbulent, uidiz'ed, ebullient state, and in which processone fluidi'zed phase is caused to pass through a second fluidized phase.My invention and proc= ess is specically directed to an improved methodof preparing a mixture of hydrogen and carbon monoxide from methaneand/or' natural gas.

It has, heretofore, been known in the art to Contact gases and solids bypassing the gases upwardly through an enlarged treating zone, con;taining a body of finely divided solids to be corri tacted, at acontrolled Velocity to maintain the solids in the treating zone inV aquasi-liquid like state. Under properly controlled conditions, thesubdivided solid particles are not only maintained in a highlyturbulent, quasi-'liquid and ebulli-j ent state, but there exists arapid and overall circulation of the nuidized solids throughout thefluid bed. y

Processes of this character, wherein iluidized solids are contacted withgases, have a number of inherent and important advantages. For ex-rample, intimate contact between the gases and the fluid subdividedsolids is secured. It is also possible to maintain a substantiallyuniform tem= perature throughout the bed as a result of the extremelyrapid transfer oflheat from one section of the bed to the other becauseof the rapid circulation of the fluid subdivided solids. Furthermore,due to the rapid transfer of heat between the solids under theseconditions, it is possible to readily add or extract heat from the massat an extremely rapid rate,

Fluid operations of the character described for contacting flnesubdivided solids and gases have found extensive application in variousreduction reactions, polymerization processes, exothermic andendothermic reactions, processes for the bonization of nely divided coaland similar op erations. Specific processes i'n which the solid fluidtechnique have been very successfully e`mployed, are processes involvingthe treatment of petroleum oils, such as catalytic cracking operations,polymerization operations, and the like. The fluid technique has alsobeen successfully utilized in synthesis of hydrocarbons, such as theFischer synthesis reactions' both for the production of synthesis gasitself and for the reaction of oxides of carbon and hydrogen for theproduction of hydrocarbon constituents containiiigY one or more carbonatoms in the molecule; Thus, while the contacting of finely dividedsolids and gases in a iiuidized bed, as presently practiced, has foundextensive application, there are certain inherent limitations in some ofthe proc'- esses as now practiced Which have thus far pre= ventedadaptation in many other elds and which have limited its efficiency inmany fields in which it is now employed.

In some operations, for instance, as in hydro-'- carbon synthesisoperations, the overall rapid, swirling effect obtained by thecirculation of solids through the reaction zone' may be undesirablebecause it is not possible to segregate and separate from the reactionzone, a stream of solids which are anythingmore than an averagey mixtureof solids contained in the zone. Also, in many processes it is desirableto carry out the operations in truly countercurrentA fashion in whichthe solids pass through the contacting zone in a general directioncountercurrent to the ow of the gas. This is particularly true when itis desired to remove spent material from the treating zone rather thanan average equilibrium mixture of solids contained in the zone, such asin purification and separation of gases and in the calcination anddistillation of solids. Also, in other operations it is of advantage tocarry out the process with concurrent now of solids and gases.Concurrent conditions of operation are unobtainable in carrying out thecontacting operation in a free, unconned fluid bed as prese entlypracticed. Furthermore, there is' a prac--Y tical .limit to the depth ofthe iluid bed which may be used. It has been found that, if the bed isexcessively deep, a surging and poundingr of the bed results which leadsto decreased treating efficiency. It is also desirable in some cases topass the gases to be treated or contacted suce cessively through twoseparate fluidize'd beds in open free communication with each other. Ithas also been found that in carrying out'th con- 3 tacting of gases andsolids in a fluidized bed reactor of the type described, all excess gas,in addition to that which is used to fluidize the solids, tend toagglomerate rapidly into large bubbles which find their way through thebed with imperfect contaet with the subdivided solids.

One purpose of my invention is to provide an improved method of, andapparatus for carrying out the contacting of gases and solids in thepresence of a fluidized bed of the type described which would not besubject to the limitations mentioned, and which will permit the flowingof one fluidized phase through a second separate and distinct fluidizedphase. Another important object of my invention is to provide animproved method of rapidly and effectively separating fractions ofsubdivided solids of difthe scope of which will be understood bysubsequent descriptions.

My invention finds specific application in the production of synthesisgases suitable as feed gases for the synthesis reaction discussedheretofore. The synthesis gases comprising hydrogen and carbon monoxidecan be produced from hydrocarbons, particularly from methane or fromnatural gas. The reaction comprises, generally, oxidizing hydrocarbonswith a reducible metal oxide. This procedure, per se, is old in the artsince there are many disclosures concerned with the use of reduciblemetal oxides, such as oxides of iron, chromium, copper, nickel,manganese and zinc for the oxidation of hydrocarbons comprising methaneto produce hydrogen and oxides of carbon, particularly, carbon monoxide.These reactions are generally conducted at temperatures in the rangefrom about 1400 F. to about 2000 F.

I have now discovered that, providing the character and the type ofcatalyst is controlled within the reaction zone, that is, the zone wherethe synthesis gases are produced from hydrocarbons comprising methane,unexpected desirable results will be secured. In accordance with myinvention, I control the catalyst within the reaction zone bymaintaining therein two separate and distinct phases of uidized,subdivided solid catalyst particles. In the bottom of the reaction zone,I maintain a suspended fluid bed of finely divided particles of areducible metal oxide which functions as an oxygen carrier to oxidizehydrocarbons. In the upper section of the reaction zone, adjacent to thelower fluid bed, I maintain a suspended fluid bed of finely dividedparticles of a suitable reforming catalyst. The two solid phases in myreaction vessel are maintained relatively separate and distinct fromeach other by virtue of a difference in densities, the lower layer beingmade up of particles of greater density than those contained in theupper layer. The reducible metal oxides which I choose to use aresubstantially heavier than the reforming catalysts.

Assuming that FeO is to be used to transfer 4 oxygen to the gas phase,the following reaction represents theoretically the operation:

However, depending upon the nature of the metal oxide used more or lesscarbon dioxide and water vapor will be formed along with the carbonmonoxide. It is highly desirable to use the water vapor and carbondioxide in the formation of synthesis gas and this is done byreformation of part of the methane charge with this water vapor andcarbon dioxide. It is apparent, therefore, that two reactions areinvolved, first the oxidation of the methane and secondly, thereformation of residual methane with carbon dioxide and water vapor. Thefirst reaction involves contacting the methane with the metal oxidewhile the second reaction involves contacting the products of the firstreaction with a reforming catalyst.

Other considerations involve the heat balance. Considering first theoxidation reaction, in this process the reduced metal oxide is removedfrom the bottom of the synthesis gas generator and burned with air in aseparate vessel generally operated at lower pressure in order to avoidhaving to compress the air required more than necessary. This oxidationof the metal by air is carried out at a temperature to 200 F. greaterthan that existing in the synthesis gas generating zone. The oxidationof the metal oxide causes the liberation of a large amount of heat ofoxidation. This heat is absorbed by the metal which is charged to theburning vessel in large excess over and above that theoreticallyrequired to oxidize the methane or other hydrocarbon gas used. The hotmetal and metal oxide is carried back to the oxidation vessel and itssensible heat content serves to support thermally the reactions thereinoccurring, together with the heat contained in the feed.

The reaction occurring in the methane reforming zone is endothermic, asindicated, and to support this reaction heat is supplied from the hotsolids present in the methane oxidation zone in one modification of theinvention. Thus, the reforming catalyst may be caused to flow upwardlythrough these hot solids to acquire heat in a manner hereinafter morefully disclosed. Furthermore, the reforming catalyst may be withdrawnfrom the reforming zone and passed through a heating zone also in amanner hereinafter more fully disclosed. A third modification involvesinternal circulation of the reforming catalyst from the upper to thelower zone where the catalyst acquires heat.

The reforming catalyst may comprise any suitable catalyst, as forexample, nickel on magnesia, nickel or Portland cement, or compoundscontaining manganese and cobalt and the like. Under suitable conditionsthe following reforming reactions occur:

In order to carry out my process, I find it desirable to add 1/2 mol ofoxygen by means of the metal oxide to the lower portion of the synthesisgas generation vessel. This quantity of oxygen is sumcient to produceone mol of carbon monoxide per mol of methane charged. To

whatever extent that carbon dioxide and water vapor are formed therewill be residual unburned methane in the gases leaving the burning zone.It is this residual methane which reacts with the water vapor and carbondioxide in the reforming zone, although provision is made for addingadditional methane directly to the reforming zone.

I have found that it is highly desirable that the reactions be carriedout as I have indicated, namely, oxidation of the natural gas in alower` zone followed by reformation of the oxidation products in anupper zone. It is necessary to avoid having oxidation reactions occur inthe reformation zone. In other words, it is highly desirable to avoidcontacting the carbon monoxide and hydrogen produced in the top zonewith metal oxide which might cause degradation of the products to watervapor and carbon dioxide. This is brought out by the followingdescription. of experimental work carried out to demonstrate thisprinciple of operation.

A number of operations were conducted in which the feed gases to thetreating zone were passed through a mixture of oxidizing and reformingcatalyst. In other` operations, the feed gases to the treating zone werepassed successvely through beds of oxidizing catalyst and reformingcatalyst, The oxidizing catalyst comprises FezOs, While the reformingcatalyst comprised nickel on magnesia. Equal parts by volume of therespective catalysts were employed The results of these operations aresummarized inthe following table:

ent invention, the reaction zone is filled, or partially filled, withpacking or dispersing elements adequately spaced to provide a labyrinthof discontinuous passageways in which the gases are in contact with thefinely divided solids, which are maintained in a quasi-liquid condition.These dispersing or packing elements prevent the overall swirling orrapid circulation of the solids throughout the full length and depth ofthe reactor, and also tend to break up and disperse the larger gasbubbles which tend to form. Furthermore, the presence of thesedispersing or packing elements provide, among other things, moreintimate and better contact between the solids and gases than would bethe case where the dispersing elements are omitted.

The size and character of the packing, as well as its employment in thetreating zone may vary appreciably. For example, the packing ordispersing elements may be dumped in thereaction or treating zone in arandom fashion, or these packing elements may be made to assumepredetermined geometric patterns. In cases where it is desired merely toavoid rapid overall recirculation of the solid particles throughout thereaction zone, the packing elements may be so spaced as to avoidextended uninterrupted flow of the gases through the reactor whilepermitting substantial vertical now without interruption. Where it isdesired to break up the formation of large bubbles and to maintain twophases, the

[Feed rate volume gas per volume catalyst per hour=70l00.]

Separate Bed Separate Bed Mixed Beds Temperature. 1,670c F. 1,490 F.1,580 F.

Period, Hours o-ao ao-eo fio-so o-so 30-60 fio-9o o-so 30-60 60-90Methane Conversion 92 97 8l 8i 74 65 83 Hydrogen/oo 1. 9 2. o 2. 1 2.02. o 2. 1 2. 1 2. 2 3,1 selectivity CO2. percent.. 24 2 0 78 4 1 66 5231 selectivity 00..-. Q 7e 9s 100 72 96 99 34 4s 43 Carbon -do..-- 0 o oo 0 o o o 2e From the foregoing it is apparent that it is packing andspacing elements may be so ardesirable to pass the feed gasessuccessively through a bed of oxidizing catalyst and then a bed ofreforming catalyst rather than through a bed ofmixed catalyst.

The process of my invention of flowing one fluid phase through a seconduid phase, in a treating zone, is preferably carried out by the use ofsolid non-fluidized packing material which is positioned in the treatingzone. It is to be understood that my invention will nd application inoperations in which it is desired to carry out thev operation witheither concurrent or countercurrent flow of one phase of the powder withrespect to the gases. The invention is directed and is applicable to allprocesses in which solids and gases are contacted, and in which thegases to be treated or contacted are passed upwardly through an enlargedreaction zone containing a body of nely divided solid particlesmaintained in two phases at a velocity sufficient to maintain the finelydivided solid particles in a uidized, quasi-liquid or ebullient state.My invention is applicable to operations in which the finely dividedsolids are continuously introduced into the reaction zone and a streamof solid particles is continuously removed therefrom, as well as, tooperations in which a body of finely divided solids is maintainedwithinvthe treating zone.

InA accordance with a modification of the presranged as to preventextended and uninterrupted vertical flow of the gases through thereaction zone. The dimensions and the type of the packing elementsutilized may be varied considerably, depending upon the type of thereactor employed, the velocity used, the particular reaction beingcarried out and the character and particle size of solids beingsuspended. In general, the packing may vary from a minimum dimension of1A, inch to a maximum dimension of 12 inches or more. Packing elementsof the saddle type, having a maximum diameter of 1 inch to 2 inches (forexample Berl saddles), are particularly suitable for most reactors ortreating zones. The packing or spacing elements should be shaped andarranged within the reactor so as to avoid extended horizontal surfaceson which the solid particles undergoing treatment can settle andcollect.

The reaction zone or treating chamber may have packing elements ofdifferent sizes in different vertical sections of the chamber. Forexample, the upper section of the chamber may be filled with relativelysmall packing elements and the bottom section lled with relativelycoarse packing elements. Invsome cases it mightl be of advantage to havethe coarse packing at the top and the fine at the bottom. Different sizepacking in top and bottom of the contacting. zone is of particularadvantage in effecting separation and class'ication of subdividedsolids, and when it is desired'to maintain two separate and distinctbeds of uidized solids in a single reactor.

When the space occupied by the packing is not an important factor, thepacking elements may be in the form of solids balls, spheres, cylinders,blocks, bricks and the like. However, where it is important to providemaximum reactor space with minimum volume occupied by the packing orspacing elements, it is preferable to provide elements which give amaximum surface. These elements may, for example, be in the shape ofhollow cylinders, U-shaped elements resembling saddles, wire turnings,wire helices and the like. Raschig rings may be used as such. When usingwire helices as packing elements, it is preferred to provide burrs orcrimps in the wire as base points around the circumference to avoidinterlocking of coils. When using saddle shaped elements, the elementsshould be designed to prevent close nesting of one saddle in another.

The packing or spacing elements may be made of any desired materialcapable of withstanding the conditions of operation. In cases where thereactor is adapted to carry out catalytic reactions, thespacing elementsmay or may not have catalytic activity.

In order to successively maintain a quasiliquid phase of subdividedgases Vand solids in the passage-ways between the packing elements, thesubdivided solids or powder should be of such character as to be able toow freely down through the interstices of the packing elements withoutbecoming packed or agglomerated in the absence of an upflowing fluid.This quality of free flowing in the interstices of the packing in theabsence of a suspending fluid is a function of factors, among whichinclude the density of the subdivided particles, particle size,contacting zone size with respect to length as to width and particlesize distribution. Thus, the finely divided solids used in the presentinvention must be of such particle size distribution so as to be freeflowing without the aid of aeration. By this is meant, for example, thatif a body of said solids having all sides and the bottom supported, hasthe support on one side removed, the body will ow out that side in sucha way as to leave asubstantially, uniformly inclined surface. As pointedout heretofore, the body is free flowing if it will flow downwardlyfreely through the packing in the absence of aeration without bridging.In general, this characteristic is influenced by the content of fines inthe subdivided solids having a diameter less than about 20 microns.Usually, the content of such fines should not be greater than about 12%by volume since a percentage greater than this will render subdividedparticles having particle distribution in the range from about 20microns to 200 microns nonfree flowing. If the subdivided particles arefree flowing, it is possible to fluidize the subdivided particles in theinterstices of the packing regardless of the relative sizes of thepacking, and the particle sizes of the subdivided particles providingthe packing is sufciently large to provide intertices each having adiameter greater than the diameter of the largest particle in thesubdivided solids. In general, the packing should be such as to provideinterstices having a length as compared to diameter of not greater than15 to 1. Also, the packing should be at least about times as large asthe largest particle to be fluidized.

A further illustration of free flowing sub- Operation Operation A BSilica-Alumina Catalyst Micron Size:

.l .1. .8. 28.5 29.6. Free Flowing Through Interstlces of Packing (NoAeration) No Yes Successful Fluidizatlon In Interstices of Packing NolYes 1 Secured surging and channeling.

In these and similar operations, the reactor size with respect to lengthas compared to width'was 15 to 1 or less. The packing comprisedcommercial packing of the size from about 1A to 12 inches, generally, inthe range from 1/4 to about 2 inches. Commercial type packings wereused, such as Berl saddles. The velocity2 of upowing gas was in therangefrom about 0.1 to 1.5 feet per second. Y

As another example, an iron catalyst having a micron size less than 44was not free owing in the absence of aeration through the interstices ofthe packing. This iron catalyst could not be successfully iiuidized in apacked zone. On the other hand, an iron catalyst having a micron size inthe range from about to 250 flowed freely through the interstices of thepacking and could be successfully fluidized.

Also, if a silica catalyst impregnated with alumina, as previouslydescribed, has a uniform micron size of about 45, it will neither flowfreely between the interstices of packing, nor can it be successfullyfluidized.

A further test of a free-flowing body is that if such a body is packedunder its own weight in a 60 funnel, it will flow through the funnelfreely when released at the bottom. Whether or not small subdividedparticles are free-flowing will vary with different materials asdescribed heretofore. However, its free-flowing characteristics in theabsence of aeration may be readily determined by a simple test of thecharacter indicated above. If a finely divided solid material is notfree-ilowing, it can be made so by adjusting its particle sizedistribution.

My invention is applicable to any operation wherein two fluid phases aremaintained in a treating zone, and wherein it is desirable to flow onephase upwardly or downwardly through the other phase. It is particularlyapplicable in treating zones where the reactionin one phase isexothermic, while the reaction in the other phase is endothermic. Thus,by flowing one fluid phase through the other substantial economies inheat are Secured.

My invention and specific modications of the same will be more clearlyunderstood by reference to the drawings. Fig. l is a View depicting inelevation, partly in section, an apparatus layout adapted to theproduction of synthesis gas comprising hydrogen and carbon monoxide fromnatural gases comprising methane; Fig. 2 illustrates a modification ofmy invention employed 2 Velocity in the treating zone provided no solidsarepresent.

9 in a similar process, except that internal circulation of the uid issecured; and Fig. 3 illustrates a further modification in which thereformer catalyst is circulated externally from the top of the treatingzone to the bottom, but without passing through an outside heating zone.

Similar reference characters refer to similar parts throughout theseveral views.

Referring specifically to Fig. 1, it has been found that it ispreferable that the oxygen carrying metal oxide, which may comprise ironoxide, copper oxide, or any equivalent oxide, be in a separate layerfrom the reforming powder. This powder, as stated, may comprise nickelon a carrier, or other conventional reforming catalyst. In theillustration, the lower fluid zone or phase A comprises the oxidizingmetal oxide. This oxidizing agent is maintained in a fluid ebullientstate and comprises particles having a micron size generally in therange from about 20 to about 200 microns and higher. Reduced fluid metaloxide is withdrawn from zone A in treating zone I by means of withdrawalline or conduit 2. The reduced metal oxide is passed to a burning zone8, suspended in air injected into line 2 from line 9. In burner 8, themetal in the form of fluidized bed D is reoxidized and returned to zoneA by means of conduit or pipe 3 carrying conventional gas taps t intowhich fluidizing gas is injected for the purpose of causing the solidsto flow freely.' The natural gas comprising methane is introduced intotreating zone I by means of line Ll and is distributed evenly throughouttreating zone I by means of pierced plate or other distributing means 5.The velocity of the uplowing gas is sufficient to maintain the smallsubdivided particles in zone A in a fluid ebullient state. The metaloxide is introduced in sufficient quantity to supply 1/2 mol of oxygenper mol of methane in the natural gas. Stated otherwise le pound mol ofoxygen is supplied for each pound atom of carbon present in the naturalgas. A small amount may be supplied in excess of this quantity ifdesired in order to form some carbon dioxide and water Vapor in theproducts which will supply heat which may be lost by radiation from thereaction vessels. The methane in flowing through lower Zone A isoxidized in this zone. The oxidized gases are then passed into the lowerlevel of iiuid zone or phase B in which the gases are reformed ashereinbefore described. Zone B contains small subdivided ne solids in aiiuid state, and consists, as mentioned, of suitable reforming materialsuch as nickel on magnesia, or Portland cement, or the like. As pointedout, heretofore, it is preferred that treating vessel I contain packingelements P spaced apart as indicated throughout zones A and B. The upperlevel of the second fluid phase, cornprising the reforming catalyst, ismaintained at level C. The reforming catalyst is withdrawn through pipe6, carrying gas taps t for uidizing the catalyst, carried in suspensionin an inert gas such as steam introduced through line I into 8 where itis formed into a dense, fluidized bed E heated by combustion fumes frombed D and by the heat transfer from the hot solids in D as explainedpresently. The thus heated reforming catalyst is withdrawn from burneror heater t and returned to zone B of Vessel I, via a standpipe IIcarrying the usual gas taps t. Thus, the reheated reforming catalyst inthis modification is returned to zone B directly without passing throughzone A.

It is to be noted that in heater 8 there is an intermediate zone betweenI and I' wherein there l@ is a mixture of metal oxide and reduced metaloxide and reforming catalyst. Thus, heat is imparted to the reformingcatalyst by physical contact with the hot metal oxide in this mixingzone as well as by the hot combustion fumes from zone D.

Treating Zone i may contain inlet conduits 20 and 2! disposed with theirupper ends at the interface I between zones A and B for the purpose ofintroducing carbon dioxide or methane, or both.

In the modication shown in Fig. 2, the reforming catalyst in Zone B iswithdrawn through line Ei and discharged into line 4, and thereaftercarried in suspension with the natural gas in line 4 into the bottom oftreater I. The more buoyant reforming catalyst passing upwardly throughZone A containing hot metal and metal oxide, thus acquiring heat andthereafter passing into zone B with a sufficient heat content to supportthe endothermic reaction therein occurring in conjunction, of course,with the heat content of the gases passing from zone A to Zone B.Otherwise, the operation of the apparatus is similar to that describedin connection with the operation of the apparatus of Fig. l, i. e., themetal in zone A is transferred to a burner vessel for reoxidation, andthen returned to zone A via line 3.

Fig. 3 illustrates a, modification similar to that described withrespect to Fig. 2. However, the layout of Fig. 3 differs from that ofFig. 2 in that instead of external recycling of the reforming catalystthrough the lower bed of the oxidizing catalyst, internal draft tubemeans are provided as shown by element II, the catalyst circulating inthe manner indicated by the arrows.

The reaction may be carried out at Various ternperature and pressureconditions, as for example, in the range from about l300 F. to about2000 F. However, in general it is preferred that the reactiontemperatures be in the range from about 1600 F. to l800 F'. Sunicientreforming catalyst preferably is circulated so that the temperaturebetween the two beds does not Vary in excess of about 25 F. to 50 F.

Having described the preferred embodiment of my invention, it will beunderstood that it embraces such other Variations and modifications ascome within the spirit and scope thereof.

I claim:

l. Improved process for the production of gases comprising carbonmonoxide and hydrogen from hydrocarbon gase which comprises passinghydrocarbon feed gases upwardly through a Zone containing nelysubdivided hot solid particles of a reducible metal oxide maintained inthe form of a fiuidized bed in a treating Zone, said metal oxideparticles being maintained at a temperature suiicient to cause theparticles to react with the hydrocarbon to produce a gaseous mixture ofhydrogen, carbon monoxide, carbon dioxide, steam and unreactedhydrocarbon gases, then passing resulting product gases through acontiguous zone containing subdivided hot solid particles of a reformingcatalyst also maintained in the form of a iiuidized bed, the said bed ofiiidized reforming catalyst being maintained at a temperature sufcientto cause the steam-hydrocarbon and carbon dioxide-hydrocarbon reactionsbetween these components of the aforesaid product gases from the rsttreating Zone to produce additional hydrogen and carbon monoxide,maintaining relatively larger solid nonr fluidized packing in saidtreating zone, and withdrawing product gases containing hydrogen and 11carbon monoxide from an upper portion of said second bed.

2. Process for the production of synthesis feed gases comprising carbonmonoxide and hydrogen from hydrocarbon gases vwhich comprises, passinghydrocarbon feed gases upwardly through a zone of nely subdivided solidparticles of a reducible metal oxide maintained in a fluid ebullientstate in a treating zone, maintaining the said metal oxide particles ata temperature sufficient to cause the particles to react with thehydrocarbon to produce a gaseous mixture of hydrogen, carbon monoxide,carbon dioxide, steam and unreacted hydrocarbon gases, then passing saidgases through a zone of more buoyant, finely subdivided particles of areforming catalyst maintained in a fluid ebullient state adjacent tosaid metal oxide in said treating zone, said reforming catalyst beingmaintained at a temperature conducive to reforming to cause thesteam-hydrocarbon and carbon dioxide-hydrocarbon reactions be tweenthese components of the aforesaid product obtained from the first zoneto produce additional quantities of hydrogen and carbon monoxide,maintaining relatively larger lsolid non-fluidized packing in saidtreating Zone, withdrawing treated gases from the top of said treatingZone,

`withdrawing reforming catalyst from the top of said treating zone andintroducing said reforming catalyst into the bottom of said treatingzone below the interface level of said zone of reducible metal oxide andsaid zone of reforming catalyst, whereby the more buoyant reformingcatalyst flows upwardly between the interstices of said packing andthrough the zone of said reducible metal oxide.

3. Process as defined by claim 2 in which said reducible metal oxide isan oxide of a metal selected from the group consisting of iron, cobaltand nickel.

4. Process as defined by claim 2 wherein the reducible metal oxide is anoxide of a metal selected of the group consisting of iron, cobalt andnickel, and wherein the temperature in the treating zone is maintainedin the range from Y state separately returned to the respective bedsfrom which they were withdrawn.

6. The method of forming a gaseous mixture containing carbon monoxideand hydrogen which comprises providing a conversion zone contain'- ing afiuidized bed of powdered iron oxide and above that a second separatecontiguous fluidized bed of a powdered reforming catalyst, both bedsbeing disposed within the same generally confined space, feeding a gaspredominately methane to a lower portion of the first named bed andcausing it to flow therethrough at a rate sufcient to maintain the saidfirst named bed in a fiuidized state, thereafter permitting the productfrom the first named bed to ow through the second named bed containingreforming catalyst at a rate suicient to maintain the bed of reformingcatalyst in a fluidized state, maintaining the temperature of the bedcontaining the reducible metal oxide at temperatures effecting oxidationof the said methane, causing the formation of a gaseous mixture ofhydrogen, carbon monoxide, carbon dioxide, steam and unreactedhydrocarbon gases and resulting reduction of the said metal oxide bywithdrawing reduced metal oxide, charging it to a heating zone where itis contacted with an oxygen-containing gas to reoxidize at least aportion of the reduced metal oxide and impart heat to the remainder andreturning the thus reoxidized and reheated metalV oxide to the fiuidizedbed of reducible metal oxide, maintaining reforming temperatures tocause the steam-hydrocarbon and carbon dioxide-hydrocarbon reactionsbetween these components of the product of the rst named zone to produceadditional hydrogen and carbon monoxide in the bed of reforming catalystat least in part by withdrawing reforming catalyst from the iiuidizedbed thereof, charging it to a heating zone where it is contacted withhot gases in order to increase its heat content and thereafter returningthe reheated reforming catalyst directly to the fluidized bed ofreforming catalyst, and recovering from another portion of the bed ofiiuidized catalyst a product containing hydrogen and carbon monoxide.

References Cited in the le of this patent UNITED STATES PATENTS SymondsMar. 10, 1953

1. IMPROVED PROCESS FOR THE PRODUCTION OF GASES COMPRISING CARBONMONOXIDE AND HYDROGEN FROM HYDROCARBON GASES WHICH COMPRISES PASSINGHYROCARBON FEED GASES UPWARDLY THROUGH A ZONE CONTAINING FINELYSUBDIVIDED HOT SOLID PARTICLES OF A REDUCIBLE METAL OXIDE MAINTAINED INTHE FORM OF A FLUIDIZED BED IN A TREATING ZONE, SAID METAL OXIDEPARTICLES BEING MAINTAINED AT A TEMPERATURE SUFFICIENT TO CAUSE THEPARTICLES TO REACT WITH THE HYDROCARBON TO PRODUCE A GASEOUS MIXTURE OFHYDROGEN, CARBON MONOXIDE, CARBON DIOXIDE, STREAM AND UNREACTEDHYDROCARBON GASES, THEN PASSING RESULTING PRODUCT GASES THROUGH ACONTIGUOUS ZONE CONTAINING SUBDIVIDED HOT SOLID PARTICLES OF A REFORMINGCATALYST ALSO MAINTAINED IN THE FORM OF A FLUIDIZED BED, THE SAID BED OFFLUIDIZED REFORMING CATALYST BEING MAINTAINED AT A TEMPERATURESUFFICIENT TO CAUSE THE STEAM-HYDROCARBON AND CARBON DIOXIDE-HYDROCARBONREACTIONS BETWEEN THESE COMPONENTS OF THE AFORESAID PRODUCT GASES FROMTHE FIRST TREATING ZONE TO PRODUCE ADDITIONAL HYDROGEN AND CARBONMONOXIDE, MAINTAINING RELATIVELY LARGER SOLID NONFLUIDIZED PACKING INSAID TREATING ZONE, AND WITHDRAWING PRODUCT GASES CONTAINING HYDROGENAND CARBON MONOXIDE FROM AN UPPER PORTION OF SAID SECOND BED.